Interchangeable electrical connection for carbon brushes



Op@ 2s 1924. 1,513,355

R; H. WARD INTERCHANGEABLE E LCTRI-GAL CONNECTION FOR CARBON BRUSHES Filed aan. 1jr. 1923 ATT N `the brush and this invention is Patented Oct. 2S, 1924.

RICHARD H. WARD, OF QUEENS, NEW YORK.

INTERGHANGEABLE ELECTRICAL CONNECTION FOR CARBON BRUSHES.

Application filed January l?, 1928. Serial No. 613,124.

To all whom t may concern.'

Be it known that I, RICHARD H. IVARD, a citizen of the United States, residing at Queens, in the county of Queens and State of New York, have invented a certain new and useful Interchangeable Electrical Connection for Carbon Brushes, of which the following is a specification.

This invention relates to improvement in electrical connections for carbon brushes of dynamo electric machines, and is more particularly directed to an improved manner of associating a flexible metallic conductor with such brushes.

It is well lrnown that electrical connections with carbon brushes must be such as to maire the. best possible electrical connection between the connector and brush in order to preclude undue resistance and increasey t-he conductivity of the connection.

Many improvements have been made from time to time to insure better electrical connection between the flexible conductor and particularly directed for accomplishing this result in a simple, although more eiiicient manner than has heretofore been attained.

It has normally been the practice to chamber the brush to receive one end of the flexible connection and screws, bolts, rivets and other similar means have been employed to clamp such end of the conductor within the chamber in such manner that the conductor will be clamped tightly to the base of the chamber and at this point make a good electrical contact therewith.

The present invention goes further in that it contemplates the expanding of the end of the conductor within the chamber in such manner that it will not only form a good electrical Contact with the base of the chamber, but will also form a similar contact with the side walls of such chamber, with the result that I obtain a greater conductive contact between the parts and thus reduce the resistance in the connection. Furthermore7 the means for expanding and holding the end of the conductor within the chamber is forced into intimate contact throughout an extended surface with the conductor and serves to further increase the conductive engagement between the parts.

Another important feature of the invention resides in the fact that the connector of this invention is se constructed that its parts may be assembled to form an interchangeable unit which is adapted to be brought into cooperative relation with the brush and readily and expeditiously associated therewith to secure the conductor to the brush until such time as it is desired to replace the brush by another brush whereupon the conductor may be readily removed from the old or worn brush and easily and expeditiously associated with the new brush.

In prior practice, conductors generally have been so associated with their cooperating brushes that when the brush is discarded for any reason, the conductor is so associated therewith that it must also be discarded.

The conductor of the present invention however may be successfully associated with many brushes and is such that it will cooperate with the successive brushes in the same efiicient manner as it initially cooperated with the first brush. This feature of the invention enables the conductors to be completely prepared during their course of manufacture for association with any brush and no time need be lost at the time of securing the conductor to the brush in the preparation of such assembly.

Heretofore it has been usually necessary to prepare the conductor for cooperation with the brush at the time of securing the parts together.

A further feature of the invention resides in the provision of novel means for precluding the parts from working loose, so that when they are brought into assembled relation, they may be locked in this condition until manually released to permit of their detachment.

Features of the invention, other than those specified, will be apparent from the hereinafter detailed description and claims, when read in conjunction with the accompanying drawings.

he accompanying drawings illustrate different practical embodiments of the invention, but the constructions therein shown, are to be understood as illustrative, only, and not as defining the limits of the invention.

Figure l is a perspective view of a brush and flexible connection assembled in aCCOIdance with the present invention,

Figure 2 is a perspective view of the brush with the connection removed.

Figure is a front eleyation of the upbe associated. The anchor plate 3 is associated with the recess 2 and a screw 19 provided with a tapering head Q0 is passed through the perforation in the expanding member through the passage 5 in the brush and screufed into the tapped hole 6 of the anchor plate. :is the screw is tightened, the tapered head thereof will wedge into the frustoconical portion 1S of the expanding' member and draw said expanding member in the direction of the base of the recess 4, thereby causing the frustoconical portion 8 to be forced into the tapered hole of the terminal eye 1Q. A wedging action will be set up which will not only cause the inner face of the eye to tightly bear against the hase of the recess et, but will also cause the radial expansion of the eye for the purpose of forcing its outer circumference into tight engagement with the side all of the recess. In other words, the frustoconical portion 18 of the expanding member will exert a force on the eye of the cable in a direction against the base of the recess and also against the side walls of the recess and by so doing will force the eye into intimate conformity7 with all parts of the recess 4 and positively insure proper electrical contact therewith.

Furthermore, a narrow iange 21, which. extends around the base of the frustoconical portion and forms the outer margin of the part 15 will bear against the outer face of the eye. Accordingly, the eye will be in proper electrical contact not` only with all surfaces of the recess et, but also with the long tapering surface of the frustoconical member and with the inner face of the flange 21, so that every part of the surface of the eye will have close electrical contact either with the brush proper or with some metallic part having proper electrical contact with the brush proper. lliccordingly, maximum current capacity in joints thus formed is assured and the resistance is minimiZed.

In order to preclude the screw 19 from working loose, this screw may be locked in position in the simple and etiicient manner shown in Figures 3, 4 and 6. That is to say, small tongues 22 preferably, though not essentially, three in number, may be stamped up from the frustoconical portion so as to normally partake of parallel relation shown in Figure 6. These tongues are of a width substantially equal to the width of the slot 23 in the screw head, so that after the screw has been tightened and this slot moved into juxtaposition with one of these tongues, that particular tongue may be bent over as shown in Figures 3 and et, so as to lie within the slot 23 and thus lock the screw against inadvertent rotation. When it is desired to remove the parts however, the tongue may be readily bent up and the screw removed. In this manner, I obtain a positive lool;

withoutthe employment of any extraneous means and insure the integrity of the parts, so that they cannot possibly inadvertently work loose under vibration. rEhe parts will maintr'n their proper assembled relation until it is desired to dismantlel them, for the purpose, for example` of replacing a new brush for one which has been worn downv In this event, it is only necessary to remove the screw and retract the assembled eyelet and expanding member together with the anchor plate and thereupon reassemble these parts on the new brush. It thus becomes apparent that the connector parts of this invention are efliciently interchangeable and that said parts may be used over and over with successive brushes. This obviates the necessity of providing new flexible conductors when installing new brushes.

The foregoing detailed description has dealtwith the brushes which employ single connecting cables. However, the present invention is readily adaptable for use in brushes employing cables in pairs and in Figure 9 I have shown the manner in which the invention may be applied to a brush of this character.

In such a brush, both faces of the brush are provided with recesses 4t and cooperating channels 10. which are juxtaposed on the opposite sides of the brush. Anchor plates are dispensed with and a cable with a cooperating expanding member, as shown in Figures 5 and G. is associated with each of these recesses. Then, instead'of screwing the screw into an anchor plate, the screw is threaded into a tapered nut 2s, which is seated in the expanding member opposite to the one through which the screw is passed. By tightening the screw, both the tapered screw head and tapered nut are simultaneously drawn toward one another, the nut performing the same function on its associated expanding member as the tapered screw head exerts upon its cooperating cxpanding member, so that the eyes of both cables are simultaneously expanded within their respective recesses. The nut 24 may be slotted as shown at 25, after the manner of the screw head so that it may be locked by one of the tongues 22 in the same manner as the screw head is locked. It will be apparent from the foregoing detailed description of the invention that I obtain proper electrical contact through expansion of an eye at the end of the flexible cable and at the saine time by compression of the cable to effect proper contact at the opposite faces of the eye. By this construction, maximum surface contact is produced and the resistance due to improper contact is miniinized.

In Figure l0, I have illustrated a further modified form of construction which differs from the construction. of Figures 1-7 solely v`in the fact that the expansion .member 14 is be stamped integral from a piece of sheet metal and constitute a one-piece construction.V

ln the accompanying drawings, the single cableV il' is shown as constituting the velectrical conductor. l am aware however `that a double cable may be employed in Vlieu of the single-cable shown. Such a conductor may be formed by taking a length of cable vsubstantially twice thelength of the cable lfl shown in the drawings and doubling it upon itself and forming an eye corresponding to the eye l2 at the point where the cable is bent. The useof a double cable in vlieu of a single caole is well known to the art and it is not considered necessary to illustrate the construction as the applicability of the present invention to such structure will be apparent to those skilled in the art.

The foregoing detailed description sets forth ythe invention in some of .its preferred forms, but the invention .is to be understood as fully commensurate with the appended claims. Y Having thus fully described the invention, what l claim as new and desire to secure by Letters Patent is 1. An assembly ofthe character described embodying a brush provided in one of its faces with a circular recess, a flexible connection provided .at one end with a circular apentured eye Vof less thickness than its outside diameter, and means for expanding said eye in a radial direction within .the recess of the brushV to insure tight contact between the periphery `of the eye and side wall of the recess and to simulta-nously secure the eye to the brush.

2. An assembly of the character described embodying a brush provided in one of :its faces with a .circular recess, a flexible connection provided at one end with a circular apertured eye of less thickness .than its outside diameter', and means for forcing the eye to a seat in the base of the recess .and for simultaneously radially expanding said eye .to bring its periphery into ,tight engagement with the side wall of the recess.

3. An yassembly `of the character described embodying a brush provided in one of its faces with a substantially cylindrical recess, a iiexible connection provided at one of its ends with a substantially cylindrical terminal of slightly lesS diameter than the diameter .of the reCBSS 4of less thickness lthan its diameter, and mea-ns for vforcing the terminal toa seat in the base of the recess and s1- niultaneously radially expe tight engagement with the cylindrical wall of the recess.

4f. An assembly of the character described embodying a brush provided with a substan tially kcylindrical recess, a flexible connection `provided with a substantially cylindrical terminal having a tapering aperture therethrough, said terminal being of less liickness' than its outside diameter, a frustoconical member projecting into the tapering opening in the terminal, and means for fercing the frustoconical member into said tapering opening forV the purpose of forcing the .terminal to a tight seat in the base of the recess and to simultaneously expand the terminal in a radial direction to bring the cylindrical periphery of said terminal into tight engagement with the cylindrical wall of the recess. Y

5; An assembly of the `character described embodying a brush provided with asubstantially cylindrical'recess, a flexibleconnection provided with a substantially cylindrical terminal having a tapering aperture therethrough, a frustoconical member projecting into the tapering `opening in the terminal, means for forcing the frustoconical member intosaid tapering opening for the purpose of forcing the terminal .to a tight seat in the base vof the recess and to simultaneously eX- pand theterminal in .a radial direction to bring the cylindrical periphery of said terminal into tight engagement with the cylindrical wall of the recess, and means asso ciated with the frustoconical member and voperating independently of the forcing means for tightly gripping the iieXible connection.

6. An assembly of the character described embodying .a brush `provided with aV recess, and a passage leading from the base `of the recess through the brush, a flexible connection provided at one end with an apertured terminal adapted to be positioned in the recess, a frustoconical member lprojecting into the aperture of the terminal, a clamping y member extending through thev frustoconical member through the aperture of the terminal and `through the brush and cooperating with means at the opposite side of the brush for drawing the frustoconical member into kthe aperture of the terminal to force the terminal to a tight seat within the recess and to simultaneously radially expand vsaid terminal to cause its periphery to tightly engage the side wall of the recess.

7. An `assembly of the character described embodying a brush provided with a recess, and a passage leading from the base of Ythe recess through the brush, a flexible connection provided at one end with an apertured nding said termi-V nal to bring its cylindrical periphery into terminal adapted to be positioned in the recess, a trnstoconical member projecting' n o the aperture ot the terminal, a clamping member efztending through the iiriistocoiiical member through the aperture ot the terminal and through the brush and cooperating with means at the opposite side of the brush for drawing the trustoconical member into the aperture oi the terminal. to force the terminal to a tight seat within the recess and to simultaneously radially expand said terminal to cause its periphery to tight-ly engage the side wall of the recess, and means associated with the trustoconical member tor locking the clamping member against inadvertent loosening.

8. An assembly of the character described embodying a brush, one tace ot which is provided with a substantially cylindrical recess from the base of which a passage leads through the brush to a recess at the opposite side of the brush, a current conductor provided with a substantially cylindrical terminal having a central tapered opening, a rustoconical member associated with said opening and extending thereinto, and an anchoring member having a conical head seated in the rustoconical member and extending through the passage in the brush to the opposite side of said brush, and means at the opposite side ot said brush and associated with the recess therein for exerting a pull on the clamping member to torce the frustoconical member into the opening of a terminal to seat the te 1minal in the base of the cylindrical recess to simultaneously radially expand said terminal against the cylindrical walls of said recess.

9. An assembly ot the character described embodying a brush provided in at least one of its faces with a recess, an electrical conductor provided with a terminal having a contour corresponding' to the shape of the recess and of a thickness less than its width, and means for expanding said terminal within the recess to bring the terminal into tight engagement with the walls of the recess.

lO. An assembly ot the character described embodying a brush provided in at least one of its faces with a recess, an electrical conductor provided with a terminal of the same shape as the recess, and provided with a tapering' aperture in said terminal, an expanding member comprising a frustoconical portion projecting into the tapering recess of the terminal and having associated therewith means Jfor tightly gripping the electrical conductor adjacent the terminal tor normally maintaining the expanding member in associated relation with the terminal, whereby the terminal with its associated expanding member may be simultaneously brought into cooperative relation with the recess of the brush, and means for forcing' the 'trusteconical portion of the expanding member into the opening in the terminal while the terminal occupies the recess in the brush for the purpose of t'orcing' the terminal to a tight seat in the recess and simultaneously expanding said terminal in a radial direction into engagement with the walls ot said recess.

l1. An assembly of the character described embooying a brush provided in at least one of its faces with a recess, an electrical conductor provided witl terminal ot the same shape as the recess, and provided with a. tapering aperture in said terminal, an expand ing member comprising a frustoconical por tion projecting into the tapering recess of the terminal and having associated therewith means for tightly gripping the electrical conductor adjacent the terminal for normally maintaining the expanding member in associated relation with the terminal, whereby the terminal with its associated expanding member may be simultaneously brought into cooperative relation with the recess of the brush, and means for forcing the trustoconical portion ot the expanding member into the opening in the terminal while the terminal occupies the recess in the brush for the purpose of forcing' the terminal to a tight seat in the recess and simultaneously expanding said terminal in a radial direction into engagement with the walls of said recess, and a hammer plate integral with said expanding member and adapted to expand and overlie the top of the brush.

l2. A connector of the character described embodying an electrical conductor provided at one end with a substantially flat faced cylindrical terminal provided with a central tapering opening extending therethrough, and an expanding member embodying a rustoconical portion projecting into the tapering opening of the terminal and means for tightly gripping the electrical conductor adjacent the terminal to maintain the expanding member in assembled relation with respect to the terminal.

13. A connector ot the character described embodying an electrical conductor provided at one end with a substantially flat faced cylindrical terminal provided with a central tapering opening extending therethrough, and an expanding member embodying a sheet metal plate having a lateral extension provided with wings embracing and gripping the electrical conductor adjacent the terminal, said plate being provided with a depressed rustoconical portion extending' into the opening in the terminal.

let. A connector of the character described embodying an electrical conductor provided at one end with a substantially tlat faced cylindrical terminal provided with a centrar tapering opening extending therethrough, an expanding member embodying a. sheet metal plt'e haviig Iteral" extension provided VWithiwiiigsgembracing1rd gripping the eleef tri-'ibidh4 conductor adj 'aoent the terminal', said 'plate :being provided with a depressed frus- 5 toeoilioalportion extendihginto the opening i'n the terminal; india tongue assooiatediwith said? frust'o'oonoal"depression and adtpted to be bent over to engage with the slot of :i bolt or bolt or screw head positioned Within the frustoeonieal portion. l0 i in' testimony whereof have signedthe foregoing specification.

RICHARD H. VWARD. 

